Photosensitive member comprising a diamino compound

ABSTRACT

The present invention provides a new diamino compound represented by the following general formula [I]. ##STR1## The present invention provides also a photosensitive member and an electroluminescence device both of which comprise the diamino compound of the general formula [I] as a charge transporting material.

BACKGROUND OF THE INVENTION

The present invention relates to a new compound with a diaminostructure. The amino compound is used as a photosensitive material. Inparticular, the diamino compound can be applied to a photosensitivemember or an electroluminescence device as a charge transportingmaterial.

Many organic compounds such as anthracenes, anthraquinones, imidazoles,carbazoles and styryl derivatives, which can be used as a photosensitivematerial or a charge transporting material, have been known.

However, when the materials described above are applied, for example, toa photosensitive member, compatibility with other members, durabilityand weathering resistance are required basically as well as goodphotosensitivity and good charge transportability. The fact is thatthere are few materials meeting such characteristics as above mentioned.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a new diaminocompound.

Another object of the present invention is to provide a photosensitivemember containing the new diamino compound.

Another object of the present invention is to provide anelectroluminescence device having a charge transporting layer composedof the new amino compound.

The present invention relates to a photosensitive member having aphotosensitive layer on an electrically conductive substrate,characterized by that the photosensitive layer comprises a diaminocompound represented by the following general formula [I]: ##STR2## inwhich Ar₁, Ar₂, Ar₃ and Ar₄ represent respectively an alkyl group, anaralkyl group, an aryl group, a biphenyl group or a heterocyclic group,each of which may have a substituent; R₁, R₂, R₃ and R₄ representrespectively a hydrogen atom, an alkyl group, an alkoxy group or ahalogen atom; X represents --O--, --S-- or ##STR3## in which R₅ and R₆represent respectively a hydrogen atom, an alkyl group or an aryl group.

The diamino compound is applied to a photosensitive member or anelectroluminescence device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a dispersion-type photosensitivemember having a photosensitive layer on an electrically conductivesubstrate.

FIG. 2 is a schematic sectional view of a function-dividedphotosensitive member having a charge generating layer and a chargetransporting layer on an electrically conductive substrate in thisorder.

FIG. 3 is a schematic sectional view of a function-dividedphotosensitive member having a charge transporting layer and a chargegenerating layer on an electrically conductive substrate in this order.

FIG. 4 is a schematic sectional view of a photosensitive member having aphotosensitive layer and a surface protective layer on an electricallyconductive substrate in this order.

FIG. 5 is a schematic sectional view of a photosensitive member havingan intermediate layer and a photosensitive layer on an electricallyconductive substrate in this order.

FIG. 6 is a schematic sectional view of an electroluminescence device.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a diamino compound represented by thefollowing general formula [I]: ##STR4##

In the general formula [I], Ar₁, Ar₂, Ar₃ and Ar₄ represent respectivelyan alkyl group such as methyl and ethyl, an aralkyl group such as benzyland phenethyl, an aryl group such as phenyl and tolyl, a biphenyl groupor a heterocyclic group such as thionyl and furyl. The aryl group or thebiphenyl group is preferable. Ar₁, Ar₂, Ar₃ and Ar₄ may have asubstituent exemplified by an alkyl group (methyl and the like), analkoxy (methoxy and the like), a phenoxy group and a halogen atom.Particularly preferable Ar₁, Ar₂, Ar₃ and Ar₄ are phenyl and biphenyleach of has an alkyl group.

R₁, R₂, R₃ and R₄ represent respectively a hydrogen atom, an alkyl groupsuch as methyl and ethyl, an alkoxy group such as methoxy and ethoxy ora halogen atom such as chlorine atom and bromine atom.

X represents --O--, --S-- or ##STR5## in which R₅ and R₆ representrespectively a hydrogen atom, an alkyl group such as methyl and ethyl oran aryl group such as phenyl and tolyl.

Concrete compounds having the diamino structure represented by thegeneral formula [I] are exemplified as shown below: ##STR6##

A diamino compound represented by the general formula [I] can beprepared by a conventional method.

For example, an iodide compound represented by the following formula[II]: ##STR7## in which X, R₁ to R₄ are the same as those in the formula[I], is treated with amine compounds represented by the followinggeneral formulas [III] and [IV]: ##STR8## in which Ar₁ to Ar₄ are thesame as those in the formula [I], in an adequate solvent in the presenceof a catalyst such as a basic compound or a transition metal compoundaccording to Ullmann reaction to prepare a diamino compound of thepresent invention.

The diamino compound may be also prepared by treating a diamine compoundrepresented by the following formula [V]: ##STR9## in which X, R₁ to R₄are the same as those in the formula [I], with iodine compoundsrepresented by the following general formulas [VI], [VII], [VIII] and[IX]: ##STR10## in which Ar₁ to Ar₄ are the same as those in the formula[I], in an adequate solvent in the presence of a catalyst such as abasic compound or a transition metal compound according to Ullmannreaction.

In another procedure, a compound represented by the general formula [V]is once acetylated and then condensed with iodide compounds of [VI] and[VII], followed by deacetylation of the obtained compound to becondensed with iodide compounds of [VIII] and [IX]

As to the basic compounds for the synthesis of a diamino compound of thepresent invention, alkali metal hydroxide, alkali metal carbonate,alkali metal bicarbonate and alkali metal alkolate are generally used. Aquaternary ammonium compound and an organic base such as an aliphaticamine and an aromatic amine can be also used. Among these compounds,carbonates or bicarbonates of alkali metal or quaternary ammonium arepreferable. The carbonates or bicarbonates of alkali metal are mostpreferable from viewpoints of reaction rate and heat stability.

As to the transition metals or transition compounds for the synthesis ofa diamino compound of the present invention, metals such as Cu, Fe, Co,Ni, Cr, V, Pd, Pt and Ag and compounds thereof are used. Copper,palladium and compounds thereof are preferable from the viewpoint ofyield. As to copper compounds, almost all copper compounds known may beused without limitation. Preferable ones are exemplified by CuI, CuCl,Cu₂ O, CuBr, CuCN, Cu₂ SO₄, CuSO₄, CuCl₂, Cu(OH)₂, CuO, CuBr₂, Cu₃(PO₄)₂, CuNO₃, Cu(NO₃)₂, CuCO₃, Cu(OCOCH₃), Cu(OCOCH₃)₂. Among those,CuCl, CuCl₂, CuBr, CuBr₂, CuI, CuO, Cu₂ O, CuSO₄, Cu(OCOCH₃)₂ arepreferable because of easy availability in the market. As to palladiumcompounds, halides, sulfates, nitrates and organic acid salts may beused. The usage of transition metals or transition compounds is 0.5-500mole % on the basis of halide compound used in the reaction.

The solvents used in the reaction may be the ones known, preferablyaprotic polar solvents such as nitrobenzene, dimethylformamide, dimethylsulfoxide and N-methylpyrrolidone.

The reaction is carried out at 100°-250° C. under normal pressure orunder pressure. After reaction, the solids deposited in the reactionsolution are taken out and the solvent is removed to give diaminocompound products.

The obtained amino compounds may be used singly or in mixture.

The diamino compound represented by the general formula [I] may beapplied to a photosensitive member as a photosensitive material and isparticularly useful as a charge transporting material. The diaminocompound may be applied to a charge transporting layer of anelectroluminescence device by taking advantage of its chargetransportability.

First, it is explained hereinafter that the diamino compound representedby the general formula [I] is applied as a charge transporting materialfor a photosensitive member.

A photosensitive member of the present invention has a photosensitivelayer containing one or more diamino compounds represented by thegeneral formula [I]. A photosensitive member composed the diaminocompound represented by the general formula [I] is excellent insensitivity, charge trasportabily, initial surface potential and darkdecreasing ratio and resistivity to light fatigue caused by repetitionuse.

There are known various forms of photosensitive member. The diaminocompound of the present invention may be applied to any form ofphotosensitive member. For example, there is known a monolayer type inwhich a photosensitive layer containing a charge generating material anda charge transporting material dispersed in a binder resin is formed onan electrically conductive substrate and a laminated type in which acharge generating layer containing a charge generating material isformed on an substrate, followed by formation of a charge transportinglayer on the charge generating layer. One or more of the diaminocompounds of the present invention are used as a charge transportingmaterial.

The diamino compound works as a charge transporting material in aphotosensitive member and is able to carry very effectively electricalcharges given by charge generating materials by light-absorption.

The diamino compound of the present invention is excellent in stabilityto light. As the compound does not have a double bond, it is hardlyoxidized and excellent in ozone resistance. Therefore, a photosensitivemember excellent in repetition durability can be obtained.

Moreover, the diamino compound of the present invention has goodcompatibility with a binder resin, resulting in rare deposition ofcrystals and contribution to improvement of sensitivity and repetitionproperties. A charge generating material useful for the presentphotosensitive member is exemplified by organic substances such asbisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes,xanthene dyes, cyanine coloring agents, styryl coloring agents, pyryliumdyes, azo pigments, quinacridone pigments, indigo pigments, perylenepigments, polycyclic quinone pigments, bisbenzimidazole pigments,indanthrone pigments, squalylium pigments, azulene coloring agentsphthalocyanine pigments, and pyrrlo-pyrrole pigments; and inorganicsubstances such as selenium, selenium-tellurium, selenium arsenic,cadmium sulfide, cadmium selenide, zinc oxide and amorphous silicon. Anyother material is also usable insofar as it generates charge carriersvery efficiently upon absorption of light.

The binder resins used for forming a photosensitive layer areexemplified with no significance in restricting the embodiments of theinvention by thermoplastic resins such as saturated polyesters,polyamides, acrylic resins, ethylene-vinyl acetate copolymers, ioncross-linked olefin copolymers (ionomer), styrene-butadiene blockcopolymers, polycarbonates, vinyl chloride-vinyl acetate copolymers,cellulose esters, polyimides and styrols; thermosetting resins such asepoxy resins, urethane resins, silicone resins, phenolic resins,melamine resins, xylene resins, alkyd resins and thermosetting acrylicresins; photocuring resins; and photoconductive resins such as polyvinyl carbazole, polyvinyl pyrene, polyvinyl anthracene,polyvinylpyrrole. Any of these resins can be used singly or incombination with other resins. It is desirable for any of theseelectrically insulating resins to have a volume resistance of 1×10¹² Ωcmor more when measured singly. In order to form a photosensitive memberof a monolayer type, fine particles of a charge generating material aredispersed in a resin solution or a solution containing a chargetransporting material and a binder resin and then the solution issprayed on an electrically conductive substrate followed by drying. Athickness of the photosensitive layer is 3-50 μm, preferably 5-30 μm.The sensitivity becomes poor if the charge generating material is usedin an insufficient quantity, whereas the chargeability becomes poor andthe mechanical strength of photosensitive layer is inadequate if used toexcess. Therefore, the amount of the charge generating material iswithin the range of 0.01-2 parts by weight, preferably 0.2-1.2 parts byweight on the basis of one part by weight of the binder resin of thephotosensitive layer. The amount of diamino compound of the formula [I]as a charge transporting material is within the range of 0.01-2 parts byweight, preferably 0.2-1.5 parts by weight. on the basis of one part byweight of the binder resin. If the amount is less than 0.01 part byweight, sensitivity becomes poor. If the amount is more than 2 parts byweight, mechanical strength of the photosensitive layer and repetitionproperties become poor.

In order to form a photosensitive member of a laminated type, a chargegenerating material is deposited in a vacuum on an electricallyconductive substrate, a charge generating material is dissolved in anadequate solvent to apply onto an electrically conductive substrate oran application solution containing a charge transporting material and,if necessary, a binder resin dissolved in an appropriate solvent isapplied onto an electrically conductive substrate to be dried, for theformation of a charge generating layer on an electrically substrate.Then, a solution containing a charge transporting material and a binderresin is applied onto the charge generating layer followed by drying forthe formation of a charge transporting layer. A thickness of the chargegenerating layer is 4 μm or less, preferably 2 μm or less. A thicknessof the charge transporting layer is 3-50 μm, preferably 5-30 μm. A ratioof the charge transporting material in the charge transporting layer is0.2-2 parts by weight, preferably 0.3-1.3 parts by weight on the basisof one part by weight of the binder resin.

A photosensitive member of the present invention permits, in combinationwith the binder, the use of a plasticizer such as halogenated paraffin,polybiphenyl chloride, dimethyl naphthalene, dibuthyl phthalate ando-terphenyl, the use of an electron-attracting sensitizer such aschloranyl, tetracyanoethylene, 2,4,7-trinitro-fluorenone,5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalicanhydride and 3,5-dinitrobenzoic acid, or the use of a sensitizer suchas methyl violet, rhodamine B, cyanine dye, pyrylium salt andthiapyrylium salt.

An electrically conductive substrate is exemplified by a sheet or a drummade of metal or alloy such as copper, aluminum, silver, iron andnickel; a substrate such as a plastic film on which the foregoing metalor alloy is adhered by a vacuum-deposition method or an electrolessplating method and the like; substrate such as a plastic film and paperon which an electro-conductive layer is formed by applying or depositingelectroconductive polymer, indium oxide, tin oxide etc.

Concrete constitutions of a photosensitive member are shown in FIG. 1 toFIG. 5.

FIG. 1 shows a monolayer type in which a photosensitive layer (4)containing a charge generating material (3) and a charge transportingmaterial (2) dispersed in a binder resin is formed on an electricallyconductive substrate. The diamino compound of the present invention isused as the charge transporting material.

FIG. 2. shows a function-divided type in which a photosensitive layer iscomposed of a charge generating layer (6) and a charge transportinglayer (5). The charge transporting layer (5) is formed on the surface ofthe charge generating layer (6). The diamino compound of the presentinvention is incorporated into the charge transporting layer (5).

A photosensitive member shown in FIG. 3 is similar to that of FIG. 2 ina function divided type having a charge generating layer (6) and acharge transporting layer (5), but different in that the chargegenerating layer (6) is formed on the surface of the charge transportinglayer (5).

A photosensitive member shown in FIG. 4 has further a surface protectivelayer (4) formed on the photosensitive member of FIG. 1. Thephotosensitive layer (7) may be a function divided type having a chargegenerating layer (6) and a charge transporting layer (5).

A photosensitive member shown in FIG. 5 has an intermediate layerbetween a substrate (1) and a photosensitive layer (4). The intermediatelayer is effective in improvement of adhesivity, improvement ofcoatability, protection of the substrate, improvement of chargeinjection from the substrate into the photosensitive layer.

Materials used for the formation of the intermediate layer isexemplified by polyimides, polyamides, nitrocelluloses, polyvinylbutyrals, polyvinyl alcohols and aluminum oxide. It is desirable that athickness of the intermediate layer is 1 μm or less.

A diamino compound of the present invention represented by the generalformula [I] can be applied to a charge transporting layer of anelectroluminescent device by taking advantage of its charge transportingproperties. The application of the diamino compound of the presentinvention to an electroluminescent device is explained hereinafter.

An electroluminescent device is composed of at least an organic luminouslayer and a charge transporting layer between electrodes.

A sectional schematic view of an electroluminescent device is shown inFIG. 6. In the figure, the reference number (11) is an anode, on which acharge transporting layer (12), an organic luminous layer (13) and acathode (14) are laminated in the order. A a diamino compound of thepresent invention represented by the general formula [I] is contained inthe charge transporting layer.

A voltage is applied between the anode (11) and the cathode (14) to giveluminescence.

As to an electrically conductive material used as the anode (11) of theorganic electroluminescent device, the ones having work function of 4 eVor more are preferable and exemplified by carbon, aluminum, vanadium,iron, cobalt, nickel, copper, zinc, tungsten, silver, tin, gold, alloythereof, tin oxide and indium oxide.

As to an electrically conductive material used as the cathode (14) ofthe organic electroluminescent device, the ones having working functionof 4 eV or less and exemplified by magnesium, calcium, titanium,yttrium, lithium, gadolinium, ytterbium, ruthenium, manganese and analloy thereof.

In the organic electroluminescent device, at least one of the anode (11)or the cathode (14) is made transparent so that luminescence can beseen. A transparent electrode is formed by depositing or sputteringelectroconductive materials above mentioned on a transparent substrateto give a desired transparency. The transparent substrate is notparticularly limited so far as it has an adequate strength and is notinfluenced adversely by heat generated in deposition process during thepreparation of an electroluminescence device. Such a transparentmaterial is exemplified by a glass substrate, transparent resin such aspolyethylene, polypropylene, poly-ether-sulfone,poly-ether-ether-ketone.

A transparent electrode available in the market such as ITO and NESA isknown in which a transparent electrode is formed on a glass substrate.

The charge transporting layer (12) may be formed by depositing a diaminocompound represented by the general formula [I] or spin-coating anadequate resin-solution of the diamino compound.

When the charge transporting layer (12) is formed by a depositionmethod, its thickness is 0.01-0.3 μm in general. When the chargetransporting layer (12) is formed by a spin-coating method, itsthickness is 0.05-1.0 μm and the diamino compound is incorporated at acontent of 20-80% by weight on the basis of a binder resin.

Then, an organic luminous layer is formed on the charge transportinglayer (12).

As to organic luminous materials incorporated in the organic luminouslayer, the ones known can be used and exemplified by epitolidine,2,5-bis[5,7-di-t-pentyl-2-benzoxazolyl]thiophene,2,2'-(1,4-phenylenedivinylene)bisbenzothiazole,2,2'-(4,4'-biphenylene)bisbenzothiazole,5-methyl-2-{2-[4-(5-methyl-2-benzoxazolyl)phenyl]vinyl}benzoxazole,2,5-bis(5-methyl-2-benzoxazolyl)thiophene, anthracene, naphthalene,phenanthrene, pyrene, chrysene, perylene, perylenequinone,1,4-diphenylbutadiene, tetraphenylbutadiene, coumarin, acridinestilbene, 2-(4-biphenyl)-6-phenylbenzoxazole, aluminum trioxine,magnesium bisoxine, zinc bis(benzo-8-qunolinol),bis(2-methyl-8-qunolinolate)aluminum oxide, indium trisoxine, aluminumtris(5-methyloxine), lithium oxine, gallium trioxine, calciumbis(5-chloroxine), poly-zinc-bis(8-hydroxy-5-qunolinyl)methane),dilithium epindridione, zinc bisoxine, 1,2-phthaloperynone and1,2-naphthaloperynone. Further, general fluorescent dyes such asfluorescent coumarin dyes, fluorescent perylene dyes, fluorescent pyrandyes, fluorescent thiopyran dyes, fluorescent polymethine, fluorescentmerocyanine dyes and fluorescent imidazole dyes. Particularly preferableones are chelated oxinoides.

The organic luminous layer may be a monolayer type formed with the abovementioned luminous compounds or may be a multilayer type in order toadjust color of luminescence, strength of luminescence and the like.

Finally, a cathode is formed on the organic luminous layer, so that anorganic luminescent device in which the charge transporting layer(12),the luminous layer (13) and the cathode (14) are laminated on theanode(11) in the order is obtained. The charge transporting layer (12)and the luminous layer (13) may be formed on the cathode (14) in theorder.

A pair of transparent electrodes are bonded to an adequate lead wiresuch as nichrome wire, gold wire, copper wire and platinum wire and avoltage is applied to the electrodes so that luminant light may begiven.

An organic electroluminescence device can be applied to various kinds ofdisplay devices.

Specific examples are shown below. In the examples, the wording"part(s)" means "part(s) by weight" so far as it is not explainedparticularly.

SYNTHETIC EXAMPLE 1 Synthetic Example of the Diamino Compound [15]

The iodide compound represented by the following formula: ##STR11## of5.7 g, 4,4'-ditolylamine of 4.7 g, potassium carbonate of 3.5 g, copperpowder of 1 g and nitrobenzene of 50 g were placed in a four-neckedflask of 200 ml capacity with a reflux condenser to be treated for 24hours at 200° C. under nitrogen stream.

After reaction, nitrobenzene was removed by means of a steamdistillation method. Then, tetrahydrofuran of 100 g was added to thereaction solution and solids were filtrated. The filtrate was subjectedto silica gel column chromatography. The separated products werepurified by recrystallization from toluene-ethanol solvent to give whitecrystals of 5.0 g. The result of elemental analysis of the resultant(C₄₈ H₄₄ N₂ O ) is shown in Table 1 below.

                  TABLE 1                                                         ______________________________________                                                 C (%)      H (%)   N (%)                                             ______________________________________                                        calculated 86.75        6.63    4.22                                          found      86.72        6.59    4.18                                          ______________________________________                                    

EXAMPLE 1

The bisazo compound (0.45 parts) represented by the general formula [A]below: ##STR12## polyester resin (Vylon 200; made by Toyobo K.K.) of0.45 parts and cyclohexanone of 50 parts were placed in Sand grinder fordispersion. The dispersion solution of the bisazo compound was appliedonto aluminotype-Mylar of 100 micron thickness by film applicator toform a charge generating layer so that the thickness of dried layerwould be 0.3 g/m².

A solution containing the diamino compound [2] of 70 parts andpolycarbonate resin (Panlite K-1300, made by Teijin Kasei K.K.) of 70parts dissolved in 1,4-dioxane of 400 parts was applied onto the chargegenerating layer to form a charge transporting layer so that thethickness of dried layer would be 16 microns. Thus, a photosensitivemember with two layers was prepared.

The resultant photosensitive member was installed in a copying machine(EP-470Z; made by Minolta Camera K.K.) and corona-charged by power of -6KV level to evaluate initial surface potential V₀ (V), half-reducingamount (E_(1/2) (lux.sec)) and dark decreasing ratio of the initialsurface potential (DDR₁). E_(1/2) means an exposure amount required toreduce the initial surface potential to half the value. DDR₁ is adecreasing ratio of the initial surface potential after thephotosensitive member was left for 1 second in the dark.

EXAMPLES 2-4

Photosensitive members were prepared in a manner similar to Example 1except that the diamino compounds [3], [4] and [5] were usedrespectively instead of the diamino compound [2].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLE 5

The bisazo compound (0.45 parts) represented by the general formula [B]below: ##STR13## polystyrene resin (molecular weight of 40,000) of 0.45parts and cyclohexanone of 50 parts were placed in Sand grinder fordispersion.

The dispersion solution containing the bisazo compound was applied ontoaluminotype-Mylar of 100 micron thickness by film applicator to form acharge generating layer so that the thickness of dried layer would be0.3 g/m².

A solution containing the diamino compound [7] of 70 parts andpolyarylate resin (U-100; made by Yunichica K.K.) of 70 parts dissolvedin 1,4-dioxane of 400 parts was applied onto the charge generating layerto form a charge transporting layer so that the thickness of dried layerwould be 16 microns. Thus, a photosensitive member with two layers wasprepared.

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLE 6-8

Photosensitive members were prepared in a manner similar to Example 5except that the diamino compounds [11], [12] and [13] were respectivelyused instead of the diamino compound [7].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLE 9

The polycyclic quinone compound (0.45 parts) represented by the generalformula [C] below: ##STR14## polycarbonate resin (Panlite K-1300; madeby Teijin Kasei K.K.) of 0.45 parts and dicloroethane of 50 parts wereplaced in Sand grinder for dispersion. The dispersion solution of thepolycyclic quinone pigments was applied onto aluminotype-Mylar of 100micron thickness by film applicator to form a charge generating layer sothat the thickness of dried layer would be 0.4 g/m².

A solution containing of the diamino compound [16] of 60 parts andpolyarylate resin (U-100; made by Yunichica K.K.) of 50 parts dissolvedin 1,4-dioxane of 400 parts was applied onto the charge generating layerto form a charge transporting layer so that the thickness of dried layerwould be 18 microns. Thus, a photosensitive member with two layers wasprepared.

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLES 10-11

Photosensitive members were prepared in a manner similar to Example 9except that the diamino compounds [17] and [21] were respectively usedinstead of the diamino compound [16].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLE 12

The perylene pigments (0.45 parts) represented by the general formula[D] below: ##STR15## butyral resin (BX-1; made by Sekisui Kagaku KogyoK.K.) of 0.45 parts and dicloroethane of 50 parts were placed in Sandgrinder for dispersion.

The dispersion solution of the perylene pigment was applied ontoaluminotype-Mylar of 100 micron thickness by film applicator to form acharge generating layer so that the thickness of dried layer would be0.4 g/m².

A solution containing the diamino compound [22] of 50 parts andpolycarbonate resin (PC-Z; made by Mitsubishi Gas Kagaku K.K.) of 50parts dissolved in 1,4-dioxane of 400 parts was applied onto the chargegenerating layer to form a charge transporting layer so that thethickness of dried layer would be 18 microns. Thus, a photosensitivemember with two layers was prepared.

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemember in a manner similar to Example 1.

EXAMPLES 13-14

Photosensitive members were prepared in a manner similar to Example 12except that the diamino compounds [23] and [24] were used respectivelyinstead of the diamino compound [22].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLE 15

Titanylphthalocyanine of 0.45 parts, butyral resin (BX-1; made bySekisui Kagaku Kogyo K.K.) of 0.45 parts and dicloroethane of 50 partswere placed in Sand grinder for dispersion.

The dispersion solution of the phthalocyanine pigment was applied ontoaluminotype-Mylar of 100 micron thickness by film applicator to form acharge generating layer so that the thickness of dried layer would be0.3 g/m².

A solution containing the diamino compound [25] of 50 parts andpolycarbonate resin (PC-Z; made by Mitsubishi Gas Kagaku K.K.) of 50parts dissolved in 1,4-dioxane of 400 parts was applied onto the chargegenerating layer to form a charge transporting layer so that thethickness of dried layer would be 18 microns. Thus, a photosensitivemember with two layers was prepared.

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1.

EXAMPLES 16 AND 17

Photosensitive members were prepared in a manner similar to Example 15except that the diamino compounds [27] and [32] were used respectivelyinstead of the diamino compound [25].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemember in a manner similar to Example 1.

EXAMPLE 18

Copper phthalocyanine of 50 parts and tetranitro-copper phthalocyanineof 0.2 parts were dissolved in 98% conc. sulfuric acid of 500 parts withstirring. The solution was poured into water of 5000 parts to deposit aphotoconductive composition of copper phthalocyanine andtetranitro-copper phthalocyanine. The obtained composition was filtered,washed and dried at 120° C. under vacuum conditions.

The photoconductive composition obtained above of 10 parts,thermosetting acrylic resin (Acrydick A405; made by Dainippon Ink K.K.)of 22.5 parts, melamine resin (Super Beckamine J820; made by DainipponInk K.K.) of 7.5 parts, the diamino compound [3] of 15 parts and mixedsolution of methyl ethyl ketone and xylene (1:1) of 100 parts wereplaced in a ball mill pot for dispersion. The mixture was mixed fordispersion for 48 hours to give a photosensitive application solution.The application solution is applied onto an aluminum substrate anddried. Thus, a photosensitive layer having thickness of 15 microns wasformed.

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemember in a manner similar to Example 1 except that the photosensitivemember was corona-charged by power of +6 KV level.

EXAMPLES 19-21

Photosensitive members were prepared in a manner similar to Example 18except that the diamino compounds [15], [23] and [33] were respectivelyused instead of the diamino compound [3].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 18.

COMPARATIVE EXAMPLES 1-4

Photosensitive members were prepared in a manner similar to Example 18except that the compounds represented by the formulas [E], [F], [G] and[H] were respectively used instead of the diamino compound [3].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 18. ##STR16##

COMPARATIVE EXAMPLES 5-7

Photosensitive members were prepared in a manner similar to Example 18except that the compounds represented by the following formulas [I], [J]and [K] were respectively used instead of the diamino compound [3].

V₀, E_(1/2) and DDR₁ were evaluated on the obtained photosensitivemembers in a manner similar to Example 1. ##STR17##

In Comparative Examples 1-7, it was observed that some crystals weredeposited partially when the photosensitive layers were formed with theuse of photosensitive application solution containing the compounds of[G], [H] and [I].

The results of V₀, E_(1/2) and DDR₁ with respect to the photosensitivemembers obtained Examples 1-21 and Comparative Examples 1-7 weresummarized in Table 2 below.

                  TABLE 2                                                         ______________________________________                                                   V.sub.0 (V)                                                                           E.sub.1/2  (lux · sec)                                                          DDR.sub.1 (%)                                   ______________________________________                                        Example 1    -650      1.2        3.1                                         Example 2    -660      1.0        2.7                                         Example 3    -650      0.8        3.0                                         Example 4    -650      0.9        2.9                                         Example 5    -650      1.0        2.9                                         Example 6    -640      1.2        3.5                                         Example 7    -650      1.1        3.1                                         Example 8    -650      1.0        3.0                                         Example 9    -640      0.8        3.4                                         Example 10   -650      1.2        2.8                                         Example 11   -650      1.1        2.9                                         Example 12   -660      1.0        2.4                                         Example 13   -650      1.3        2.8                                         Example 14   -660      1.3        2.6                                         Example 15   -650      1.1        3.0                                         Example 16   -660      1.3        2.6                                         Example 17   -650      1.2        2.9                                         Example 18   +620      0.9        12.3                                        Example 19   +610      0.8        13.0                                        Example 20   +600      1.0        13.2                                        Example 21   +610      0.8        12.8                                        Comp. Example 1                                                                            +620      15.0       12.0                                        Comp. Example 2                                                                            +600      6.5        13.7                                        Comp. Example 3                                                                            +600      3.2        14.3                                        Comp. Example 4                                                                            +620      13.5       10.4                                        Comp. Example 5                                                                            +620      3.0        11.6                                        Comp. Example 6                                                                            +630      5.4        10.2                                        Comp. Example 7                                                                            +630      5.9        10.1                                        ______________________________________                                    

It is understood from Table 1 that the photosensitive members of thepresent invention, even though they are laminated types ormonolayer-types, have sufficient charge keeping ability, low darkdecreasing ratio such that the photosensitive members can be taken intopractical use and excellent sensitivity.

Further, the photosensitive members of Example 18 was respectivelyinstalled into a copying machine (EP-350Z; made by Minolta Camera K.K.)to be subjected to positively charged repetition test. Even after 1000times of copy, clear copy images excellent in gradation were formed bothat initial stage and final stage through the test and the sensitivitywas stable. Accordingly, the photosensitive members of the presentinvention were also excellent in repetition properties.

What is claimed is:
 1. A photosensitive member having a photosensitivelayer on an electrically conductive substrate, characterized by that thephotosensitive layer comprises a diamino compound represented by thefollowing general formula [I]: ##STR18## in which Ar₁, Ar₂, Ar₃ and Ar₄represent respectively an alkyl group, an aralkyl group, an aryl group,a biphenyl group or a heterocyclic group, each of which may have asubstituent; R₁, R₂, R₃ and R₄ represent respectively a hydrogen atom,an alkyl group, an alkoxy group or a halogen atom; X represents --O--,--S-- or ##STR19## in which R₅ and R₆ represent respectively a hydrogenatom, an alkyl group or an aryl group.
 2. A photosensitive member ofclaim 1, in which the photosensitive layer further comprises a resin anda charge generating material.
 3. A photosensitive member of claim 2, inwhich the photosensitive layer contains the charge generating materialat a content of 0.01 to 2 parts by weight on the basis of 1 part byweight of resin.
 4. A photosensitive member of claim 1, in which thephotosensitive layer has a thickness of 3-50 μm.
 5. A photosensitivemember of claim 1, in which the photosensitive layer comprises a chargegenerating layer and a charge transporting layer.
 6. A photosensitivemember of claim 5, in which the charge generating layer has a thicknessof 4 μm or less.
 7. A photosensitive member of claim 5, in which thecharge transporting layer has a thickness of 3 to 50 μm.
 8. Aphotosensitive member of claim 5, in which the charge transporting layercontains the diamino compound at a content of 0.2 to 2 parts by weighton the basis of 1 part by weight of a binder resin.
 9. A photosensitivemember of claim 1, in which at least one of the Ar₁ to Ar₄ is a phenylgroup or a biphenyl group, each of which may have a substituent.